“Composition” is the act or practice of creating a song, an instrumental music piece, a work with both singing and instruments, or another type of music. In many cultures, including Western classical music, the act of composing also includes the creation of music notation, such as a sheet music “score”, which is then performed by the composer or by other singers or musicians. In popular music and traditional music, the act of composing, which is typically called songwriting, may involve the creation of a basic outline of the song, called the lead sheet, which sets out the melody, lyrics and chord progression. In classical music, the composer typically orchestrates his or her own compositions, but in musical theatre and in pop music, songwriters may hire an arranger to do the orchestration. In some cases, a songwriter may not use notation at all, and instead compose the song in her mind and then play or record it from memory. In jazz and popular music, notable recordings by influential performers are given the weight that written scores play in classical music.
Even when music is notated relatively precisely, as in classical music, there are many decisions that a performer has to make, because notation does not specify all of the elements of music precisely. The process of deciding how to perform music that has been previously composed and notated is termed “interpretation”. Different performers’ interpretations of the same work of music can vary widely, in terms of the tempos that are chosen and the playing or singing style or phrasing of the melodies. Composers and songwriters who present their own music are interpreting their songs, just as much as those who perform the music of others. The standard body of choices and techniques present at a given time and a given place is referred to as performance practice, whereas interpretation is generally used to mean the individual choices of a performer.
Although a musical composition often uses musical notation and has a single author, this is not always the case. A work of music can have multiple composers, which often occurs in popular music when a band collaborates to write a song, or in musical theatre, when one person writes the melodies, a second person writes the lyrics, and a third person orchestrates the songs. In some styles of music, such as the blues, a composer/songwriter may create, perform and record new songs or pieces without ever writing them down in music notation. A piece of music can also be composed with words, images, or computer programs that explain or notate how the singer or musician should create musical sounds. Examples range from avant-garde music that uses graphic notation, to text compositions such as Aus den sieben Tagen, to computer programs that select sounds for musical pieces. Music that makes heavy use of randomness and chance is called aleatoric music, and is associated with contemporary composers active in the 20th century, such as John Cage, Morton Feldman, and Witold Lutosławski. A more commonly known example of chance-based music is the sound of wind chimes jingling in a breeze.
The study of composition has traditionally been dominated by examination of methods and practice of Western classical music, but the definition of composition is broad enough to include the creation of popular music and traditional music songs and instrumental pieces as well as spontaneously improvised works like those of free jazz performers and African percussionists such as Ewe drummers.